Slip ring apparatus are commonly used in a variety of applications to transfer electrical energy, including electrical power and/or signals over one or more channels between portions of an apparatus which experience relative rotation.
As a non-limiting example, slip ring apparatus may be used in a variety of downhole applications as components of apparatus which are adapted to be inserted within boreholes. Such apparatus may include without limitation, borehole drilling apparatus, wellbore completion apparatus, wellbore logging apparatus, and/or wellbore production apparatus.
A slip ring apparatus may be immersed in a dielectric fluid during its operation. The dielectric fluid creates the potential for a “hydroplaning effect” in which the dielectric fluid may cause the components of the slip ring apparatus to lose contact as they rotate relative to each other.
The potential hydroplaning effect may tend to increase as the viscosity of the dielectric fluid increases and to decrease as the engagement force between the components of the slip ring apparatus increases. A desired engagement force between the components of a slip ring apparatus may be provided by preloading the slip ring apparatus in order to provide the desired engagement force.
The viscosity of the dielectric fluid in which a slip ring apparatus is immersed may vary, depending upon the operational temperature and requirements of the apparatus in which the slip ring apparatus is used and the properties of the dielectric fluid.